Pulverized fuel burner



Nov. 10, 1931. H. F. SCHMIDT 1,831,466

PULVERIZED FUEL BURNER Filed Sept. 14, 1927 WITNESS INVENTOR\ 5 H-F-Schmnd'l' BY QJ\G:Q,QQAM|}A ATTORNEY v Patented Nov. 10, 1931 v umrsn s n-ms .nnnmr scnmnrnor Lmsnowna mu my-a m 'as ie n r WE$TINGHQTISE Artur oFI- cE ELECTRIC & MANUFAC U ING-C( 'MPAN A 'Q E QR TIQN' NNS L AN PULVEBIZED FUEL BURNER Applicationflled September 14, 1927. Serial No. 219,470.

My invention relates to a, method and lapparatus forburning. pulverized fuel and has for its object the provision of apowdered fuel furnace which shall be effective to corn pletely burn the fuel suspension :therein and in which-the process of combustion takes place withoutdanger of injuryito the furnace wallsadj acent the zone ofcombustion.

; Another'object of my invention is :to provide a methodof burning pulverized fuel wherein a combustion zoneis maintained in the furnace in which a turbulent mixture of fuel and-air occurs and wherein a'blankctio'f cooler medium separates the combustion :zone from the immediately adjacent-furnace walls.

In the design .of powdered fuel furnaces, d-iificulties have been encountered .due to :the high temperature of combustion of thefuel in suspension damaging the Walls oi the furs nace. Afurther difficulty has bcencncountered in so designing a furnacethatxthefuel in its passage-thcrethrough is completely burned. An alysis {of the dust escaping w th the produ ts of m u tion passing f om powdered fuel furnaces, asheretOfOre lgnown to e, has usually shown tha a sub tant al p centag o e. par icles contain 1 a cent bustible nucleus of considerable,proportion surrounded by an envelope of ash.

These and other-diificultiesare ouercome, =in

- accord wi my in e tion, by p oviding a furnace having a combustion chamberinto which P d f elwa d air a e disch rged into an intermediatezone thereof and in opposed paths whereby a combustion zone is m int ned remotefromthesutmund ng Wall and is insulated therefrom 1by-a iblanketof cooler medium. In addition,-.the"turbulence created inthe combustion zone is so great that the fuel in suspension is violently agitated while burning, thus completely removing the ash envelopes of the particles and completely burningthe fuel. I g

Apparatus embodying features of my in I vention is illustrated in theaccompanying drawings forming apart of this SpQQification, wherein: p 1 I Fig. 1 is a diagrammatic view in elevation showin myinvention as applied to a powdered uel boiler furnac'e;

Fig.2 is a central vertical sectional viewo the furnace; and,

-Fig.' 3 is a sectional view taken along the l-ine'II-I II Io-f Fig.2. a i I Referring now to the-drawings Ishow, in Fig. 1,-a :boiler furnace 10 to which powdered fuel in suspension for combustion may be supplied by any suita blemeans, in the example shown-by the centrifugal'blower 11. '1lhe fuel and its conveying medium, preferably air, enters theblower 11 by means of an inlet conduit 12 and is discharged therefrom from around {the exteriorthereof and the air for supporting combustion entering central- 1y from-the bottom, it will be apparent from a further reading of this specification that the reverse might be employed with equal advantage and the fan 16 be "considered as supplying fuel in suspension for combustion andthe fan llconsidered as supplying air to support-combustion. 1, therefore, wish it to be distinctly understood that my invention is not limited to the particular arrangement first set-forth.

Referringnow to Figs. -2 and .3, my-.improved furnace comprises .a circular outer wall structure 21 and an inner invertedicuplike well structure 22 .cooperating with the 7 we l stru tur 2 t 0 1112 1 annula wm bustion chamber 23. The outer wall structure 21 is provided with plurality of series of chordal apertures 24L communicating with the conduits 14 for the supply of fuellingsus? pension into the furnace; The apertures 2a are disposed approximately tangentially of the central circular portion vof-the annular chamber 23. Strictly speaking, the apertures are disposed in directions chordal with respect *to the inner surface ofthe walls 21, that is, lines whichare coincident with the the a ertures 26 are arran ed in o osed r:

relation to the apertures: 24.

The interior of the inverted cup-.hke wall structure 22 communicates with the conduit;

17 and the blower 16 so thatair for combustion is impelled by way of said conduityto the interior of the wall structure 22 and is discharged therefrom through the aperture 26 in a direction opposed to the direction of the suspended fuel. The two streams meet approximately mid-stream of the annular combustion chamber 23 and there create a violentturbulent mixture which is burned in this intermediate zone. By reason of the construction and arrangement of the two sets of. discharge apertures with respect to the walls of the combustion chamber, a cooling blanket of unmixed fuel is maintained between the combustion zone and the Wall from which the fuel is discharged, and a cooling blanket of unmixed air is maintained between the combustion zone and the wall from which the air is discharged.

The inverted cup-like wall structure 22 is surmounted by a conically-shaped cover 31 so as to deflect falling ash and slag toward the bottom of the furnace from whence it may be removed: in the usual manner as by a hopper 32.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various-changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the priorart or as are specifically set forth in the appended claims.

WVhat I claimis:

1 1. In a powdered fuel furnace, means defining a combustion chamber, means providing a rotating stream of pulverized fuel within said chamber, and means for injecting into said chamber a stream of gaseous media in a direction counter to the direction of movement of the fuel stream. r V

2. In a powdered fuel furnace, means defining an annular combustion chamber,

means for discharging powdered fuel into said chamber and in a direction chordal with respect to the outer surface of the chamber, and means for m ectmg an under pressure into said chamber in a direction opposed to the path of movement of the powdered fuel.

3. In a powdered fuel furnace, means defining an annular combustion chamber, means for injecting a stream of pulverized fuelinto. said chamber in-a chordal direction with respect to the outer surface of the chamber, and means for injecting a stream of air into said chamber in a direction chordal with respect tothe outer surface of the chamber and counter to the flow of the fuel stream.

4:. In a powdered fuel furnace, inner and outer walls defining an annular combustion chamber, means for injecting through one of sald walls and into said chamber a stream of pulverized fuel in a direction chordal withrespectto the inner surface of the outer wall of the chamber, and means for injecting through the other of said walls and into said chambera stream of air also in a direction chordal with respect to the inner surface of the outer wall of the chamber and counter to the direction of'movement of the fuel stream.

5. In a powdered fuel furnace, means de- 1 of the chamber and being so arranged as to direct itsstream'of mediainto said chamber in a direction counter to the direction of fiow of the streamfrom said one nozzle means.

6. In a powdered fuelfurnace, means defining an annular combustion chamber, means disposed at the outer side of said chamber for injecting pulverized fuel in suspension into said chamber in a chordal direction with respect o the outer surface of the chamber, and means disposed at the inner side of said chamber for injecting gaseous media into said chamber in a direction counter to the direction of movement of the pulverized fuel in suspen- S1OI1.

' 7 In a powdered fuel furnace, wall mem bers defining an annular combustion chamber,

'each of said wall'members being provided with nozzle means opening into the combustion chamber and arranged to direct media flowing therethrough in directions chordal with respect tothe outer wall of the combustion chamber, the nozzle means in one of the walls being arranged in opposed relation with respect to the nozzle'means in the other wall, means for supplying powdered fuel in suspension through the nozzle means of one wall,

and means for supplying air for combustion through the nozzle means of the, other wall. 8. In a powdered fuel furnace, a. circular pension through the nozzle means of one wall structure, and means for discharging air for combustion through the opposed nozzle means of the other wall structure.

9. In a powdered fuel furnace, a circular outer wall structure, an inner inverted, cuplike wall structure cooperating with the outer wall structure to form an annular combustion chamber, both of said wall structures being provided with a plurality of nozzle means disposed to inject media into the combustion chamber in directions chordal with respect to the inner surface of the outer wall structure, the nozzle means of the circular outer wall structure being disposed in opsure developing means communicating with the nozzle meansof the outer wall structure, 7 other fluid pressure developing means communicating with the interior of the wall structure-and with the nozzle means of said structure, means for supplying powdered fuel in suspension through the fluid pressure developingmeans and nozzle means-of one of the wall structures, and means for supplying air for combustion through the other fluid pressure developing means and nozzle means of the other of said wall structures.

10. A method of burning powdered fuel which comprises causing powdered fuel in suspension to move in a circular path, directing air for combustion into the moving fuel and in a direction counter to the direction of movement of the fuel, and effecting the com zone and counter to the initial direction of movement of the fuel so as to provide annular strata of relatively cool media around the combustion zone.

In testimony whereof, I have hereunto subscribed my name this 25th day of August,

1927. y HENRY F. SCHMIDT.

posed relation with respect to the nozzle xmeans of th'e inner wall structure, fluid presbustion of such fuel at the zone of its meeting with the air.

11. A method of burning powdered fuel which comprises providing a circular com bustion' zone by mixing fuel and air in the correct proportions at a temperature above the ignition point of the fuel, and then maintaining such circular combustion zone by simultaneously injecting into the zone powdered fuel in suspension and air for combustion, the powdered fuel in suspensionbeing. injected into one side of the combustion zone and in directions chordal with respect thereto and the air for combustion being injected into the opposite side of the combustion zone and in directions chordal with respect to the 

